Drafting mechanism



May 30 1939- B. HA WILLIAMS 2,160,186

DRAFTING MECHANISM Filed Nov. 14, 1938 INV ENT OR.

BY E HWILLlHMS Patented May 30, 1939 UNITED STATES PATENT GFFlCE 2 Claims.

The principal object of this invention is to provide a drafting mechanism wherein the drafting guide can be moved freely in all vdirections assuring parallel lines and easy manipulation by the operator of the drafting guide.

A further object of my invention is to provide a drafting mechanism having a minimum of complicated parts and being so constructed that the machine is self-contained and of compact structure.

A still further object of my invention is to provide a drafting mechanism that is economical in manufacture and durable in use.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing, in which:

Fig. l is a top plan view of my drafting mechanism ready for use.

Fig. 2 is an enlarged side sectional View of my drafting mechanism taken on the line 2-2 of Fig. 1.

Fig. 3 is an enlarged end sectional View of my drafting mechanism more fully illustrating its structure.

There are many types of drafting mechanisms on the market. However, these devices are complicated, require a great amount of space, and are generally difficult to use. These mechanisms resort to bulky and troublesome mechanisms and are not suitable for small boards due to their eX- treme complications. Furthermore, the mechanisms on the market are hard to operate, and are not adaptable to interchangeable drafting guides. I have overcome such objections as will be appreciated and as will hereinafter be more fully set forth.

Referring to the drawing, I have used the numeral I0 to designate the base portion of my device which acts as a drawing surface. The numeral II indicates a recess formed in this base IU as shown in the drawing. Itis to such a base that I attach my drafting mechanism which I will now describe.

The numeral I2 designates a track bar positioned Within the recess II parallel with its longitudinal center and which may have its longer marginal edges rounded to serve as a track. This member I2 is secured to the base and spaced therefrom by the use of the spacer elements I3 as shown in the drawing. I have used the numeral ill to indicate a plate element having rotatably mounted on its lower surface the four roller elements I5. These roller elements I5 have their peripheral edges concave and operatively engage the rounded marginal edges of the bar i2. Thus 5 the plate i4 can be easily moved along the track bar I2. The numeral I 6 designates rollers rotatably mounted on and above the plate I4. I have used the numeral Il to designate the horizontal arm of a drafting guide capable of being m operatively engaged by the rollers I6 which also have their peripheral edges concave for rmly engaging the longer marginal edges of the horizontal arm Il. The numeral i3 designates a vertical arm of the drafting guide as shown in 15 the drawing. At the intersection of the horizontal and vertical arms I8, I have provided my mechanism with a finger control cup 01 handle member I9 for permitting the easy manipulation of the device in use. 20

The practical operation of my device is as follows: The plate I4 will move freely along the track bar I2 through the medium of the rollers I5. This provides the vertical movement of the drafting guide I'I. Similarly, the arm I1 can be 25 moved horizontally within the rollers I6 to provide free movement in both directions for the arm I'I. Obviously, the arm I'I may be moved diagonally upwardly or downwardly and the rollers I4 will move on the track I2 simultaneously with the movement of the arm I'I through the rollers IS providing universal control of direction of movement of the drafting guide assembly. It will here be noted that in cases where a drafting guide was of such size, a similar roller assembly and track bar could be employed for the other arm of the drafting guide in order to aid in the rigidity of the device. It is also obvious that the arm i8 could be adjustably secured to the arm I'I in cases where angular lines are desired and if 40 need be, a number of drafting guide assemblies could be used of different shapes and sizes for certain types of work. The operation of the device would be the same however, and universal movement of the drafting mechanism would be obtained through the use of multiple roller and plate assemblies as shown. By providing the nger cup i9, it is merely necessary for the operator to p-lace the point of his index finger in the cup and move the entire drafting guide assembly to any position desired within the drafting area of the base member I0. The movement of the rollers permits the device to function smoothly and provides suiicient bearing surface between their central axes to prevent inaccuracy and 5' changes in the attitude of the mechanism. Thus it will be seen that I have provided a drafting mechanism which has fulfilled all of my objects and further provides a rigid and compact means of obtaining universal movement of the drafting guide assuring that all lines of the drafting guide will be parallel.

Some changes may be made in the construction and arrangement of my improved drafting mechanism Without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included Within their scope.

I claim:

1. In a drafting mechanism, a base portion, an elongated recess formed in said base portion, a track bar member rigidly secured to and spaced from said base portion Within said recess, a plate member, roller elements rotatably mounted on the lovver side of said plate member capable of operatively engaging said track bar, roller elements rotatably secured to the upper side of said plate member and directly above said first mentioned roller elements, and a drafting guide designed to be operatively engaged by Said second mentioned rollers at times; said drafting guide having a bar formed on one of its end portions extending at right angles to said drafting guide and capable of being moved in any direction through the operation of said roller elements on said drafting guide and said track bar.

2. In a drafting mechanism, a base portion, an elongated recess formed in said base portion, a track bar member rigidly secured to and spaced from said base portion Within said recess, a plate member, roller elements rotatably mounted on the lower side of said plate member capable of operatively engaging said track bar, roller elements rotatably secured to the upper side of said plate member and directly above said first mentioned roller elements, a drafting guide designed to be operatively engaged by said second mentioned rollers at times; said drafting guide having a bar formed on one of its end portions extending at right angles to said drafting guide and capable of being moved in any direction through the operation of said roller elements on said drafting guide and said track bar, and a finger control cup secured to said drafting guide adjacent the finger of said drafting guide With said vertical bar.

BENJAMIN H. WILLIAMS. 

